There is increasing interest in miniaturized technologies in diagnostics, therapeutic testing, and biomedicinal fundamental research. The same is true for the dermal studies in topical drug development, dermatological disease pathology testing, and cosmetic science. This review aims to collect the recent scientific literature and knowledge about the application of skin-on-a-chip technology in drug diffusion studies, in pharmacological and toxicological experiments, in wound healing, and in fields of cosmetic science (ageing or repair). The basic mathematical models are also presented in the article to predict physical phenomena, such as fluid movement, drug diffusion, and heat transfer taking place across the dermal layers in the chip using Computational Fluid Dynamics techniques. Soon, it can be envisioned that animal studies might be at least in part replaced with skin-on-a-chip technology leading to more reliable results close to study on humans. The new technology is a cost-effective alternative to traditional methods used in research institutes, university labs, and industry. With this article, the authors would like to call attention to a new investigational family of platforms to refresh the researchers’ theranostics and preclinical, experimental toolbox.

During the last decades several new drug formulations were developed to target the central nervous system (CNS) from the nasal cavity. However, in these studies less attention was paid to the possible drug-drug interactions in case of multi-drug therapy. In our pilot study first we compared a nasal solution and a nasal gel to demonstrate their distribution in the nasal cavity (3D printed rat skull model and histology). Due to the aspiration induced high mortality at administration of nasal solution the study was continued only with the gel formulation of quinidine. The aim of our experiments was to identify the possible functional role of P-glycoprotein (P-gp) in the drug absorption in nasal cavity and to test drug-drug interactions at nose-to-brain delivery. Therefore, a P-gp substrate model drug, quinidine was tested by intranasal (IN) administration in presence of PSC-833 (specific P-gp inhibitor) given intravenously (IV) or IN and adrenaline (IN) at low (50 ng) or high (20 μg) dose. In control animals the brain penetration of quinidine was at the level of detection limit, but in combination therapy with IV PSC-833 the brain levels increased dramatically, similarly to high dose IN adrenalin, where due to vasoconstriction peripheral distribution was blocked. These results indicate that P-gp has an important role in drug absorption and efflux at nasal cavity, while adrenaline is also able to modify the penetration profile of the P-gp substrate model drug at nasal application as it decreases nose-to-blood absorption, letting more quinidine to reach the brain along with the nasal nerves.